Here’s the issue. You can move directories using registry entries, but there will always be some unknown number of programs that assume everyone stores everything in C:\Program Files, C:\Users, C:\Documents and Settings, or other directories. So it’s better to just let your system look like everyone else’s, and use a Unix-style symlink to move directories to another drive and forget about registry hacks. Then any program, well-behaved or not, will continue to work.

Take this approach, and you can actually use Windows 7 on a 30 GB SSD and live to tell about it.

What I don’t know is if you could format two drives, link c:\program files to d:\program files, then install Windows, and have that work properly. The next time I have a system to try that on, I think I will. Of course, if you’ve tried that, I’d love to hear from you in the comments.